P<scp>ollen quantity and quality as explanations for low seed set in small populations exemplified by</scp><i>E<scp>upatorium</scp></i> (A<scp>steraceae</scp>)

Byers, Diane L.

doi:10.1002/j.1537-2197.1995.tb11564.x

Cited by 143 publications

(127 citation statements)

References 64 publications

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“…Because K. palmata may be self-incompatible, populations with few genets face lowered seed set due to mate scarcity (Byers and Meagher 1992;Byers 1995;Sipes and Wolf 1997). Thus, this type of population may be at an increased risk of extinction as a result of inbreeding depression, loss of genetic variability, and reduced sexual reproduction.…”

Section: Discussionmentioning

confidence: 97%

Genetic diversity and mating system of the threatened plant Kirengeshoma palmata (Saxifragaceae) in Korea

et al. 2006

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The endangered herb Kirengeshoma palmata, from eastern Asia, has had its population severely reduced in number through habitat loss and fragmentation. All of the individuals within five subgroups at Mt. Baek-un-san, in the southern part of Korea, were genetically surveyed by allozyme analysis. Genetic diversity levels within subgroups were relatively high, and a consistently high outcrossing rate as well as a negligible biparental mating rate were confirmed by this study. Several groups of visibly connected ramets were observed in a clustered distribution which suggested cloning. Absence of mating partner rather than pollinators decreased seed production in small mating groups. The present genetic structure of the five subgroups was probably the result of local extinction of intervening populations. Because K. palmata may be a self-incompatible species, populations with few genets face lowered seed set due to mate scarcity. Thus, this type of population may be at an increased risk of extinction as a result of inbreeding depression, loss of genetic variability, and reduced sexual reproduction. The small, genetically depauperate subgroups may need an input of seeds or plants from other populations in China or Japan in order to regenerate, but the possibility of outcrossing depression leads us to recommend outbreeding among the local subgroups of Mt. Baek-un-san to restore genetic variability.

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Section: Discussionmentioning

confidence: 97%

Genetic diversity and mating system of the threatened plant Kirengeshoma palmata (Saxifragaceae) in Korea

et al. 2006

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“…There are several options. Differences in fruit and seed set, as well as seed quality, can be largely influenced by non-genetic causes such as low availability of pollen (Byers 1995), limitation of resources needed for reproduction (Zimmerman and Pyke 1988), grazing intensity (Cierjacks and Hensen 2004), or the particular history of a population (Ouberg and van Treuren 1995). Most small populations of D. albus grow under sub-optimal environmental conditions that might impose increased stress on reproductive plants resulting in a reduced investment of maternal energy in the offspring (Oostermeijer et al 1994).…”

Section: Discussionmentioning

confidence: 99%

Relationships between Population Size, Genetic Diversity and Fitness Components in the Rare Plant Dictamnus albus in Central Germany

Hensen

Wesche

2006

Biodivers Conserv

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An increasing number of studies support the hypothesis that smaller populations face a higher risk of extinction, and declining population sizes are therefore one of the focal points in plant conservation. In small populations, loss of genetic diversity is often related to reduced reproductive fitness. For the rare Dictamnus albus in Central Germany, an earlier study had already confirmed a significant correlation between population size and genetic diversity. In order to assess whether these variables correlate with fitness components, plant height; flower, fruit and seed production; and germination were studied in a total of 11 populations of different size. In the seven populations that were sampled over two consecutive years, differences among populations and among years were tested using a Two-Way ANOVA. Co-linearity among variables was assessed using principal component analysis (PCA), followed by calculating correlations between ordination axes and both population size and genetic diversity. Plant height and flower number were uncorrelated to the other variables and, together with germination, did not show any correlation to either population size or genetic diversity. However, both size and genetic diversity of populations correlated significantly with other PCA axes that reflected reproductive components such as fruit number, seed number, seed fruit ratio, and seed mass. Our results support the idea that reproduction is hampered in small populations and raise concerns over the loss of genetic diversity in D. albus.

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“…This plant can thus be considered as an incompatible species. A sporophytic self-incompatibility system is likely because it is a common phenomenon in Asteraceae (Burt 1977;Byers 1995;Imbert et al 1996). In this system, a plant's own pollen normally does not germinate on its own stigma or on one of similar genotype.…”

Section: Breeding Systemmentioning

confidence: 98%

Biological characteristics of an invasive south African species

López-García

Maillet

2005

Biol Invasions

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Senecio inaequidens, a south African species that has recently invaded parts of Europe, especially human disturbed habitats, was examined under laboratory and glasshouse conditions to assess the germination of achenes, soil seed banks, growth of seedlings and its breeding system. These observations allowed identification of ecological characteristics that may contribute to the invasiveness of the species. Achenes derived from three populations of S. inaequidens were germinated over a wide temperature range (from 14/6°C day/night temperatures to a constant temperature of 30°C). They exhibited a rapid achene germination especially when temperatures reached 20°C. Germination of seeds from soil samples also exhibited a prolonged germination over time suggesting therefore different types of dormancy. Growth response was studied along a nitrogen gradient from 0.33 to 16.0 mmol l À1 and data were interpreted using growth analysis. Seedlings of S. inaequidens exhibited a slow growth in low nutrient availability and a rapid growth rate when exposed to high nutrient availability, which contributed to producing a large leaf area and biomass. Four types of pollination were studied in S. inaequidens. Hand-pollinations showed that S. inaequidens was mostly self-incompatible. Self-pollinated capitula only showed 7.6% viable achenes, significantly lower than insect-pollinated and cross-pollinated capitula. Some individuals were more self-fertile than others ensuring the production of some offspring in a situation of colonisation. Natural pollination occurred with generalist insects. Most of these results confirm the invasive ability of S. inaequidens.

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Pollen quantity and quality as explanations for low seed set in small populations exemplified byEupatorium (Asteraceae)

Cited by 143 publications

References 64 publications

Genetic diversity and mating system of the threatened plant Kirengeshoma palmata (Saxifragaceae) in Korea

Genetic diversity and mating system of the threatened plant Kirengeshoma palmata (Saxifragaceae) in Korea

Relationships between Population Size, Genetic Diversity and Fitness Components in the Rare Plant Dictamnus albus in Central Germany

Biological characteristics of an invasive south African species

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